Concerned residents fear the Illawarra may soon resemble a scene from Alfred Hitchcock's The Birds as sulphur-crested cockatoos create havoc in the region.The native birds have been causing damage to property by chewing through timber structures - and announcing their presence with that distinctive loud screech.A Mt Kembla woman said the birds around her home were "horribly destructive. I feed them to stop them from wrecking things".She believed the birds could have been driven closer to the coast by the inland drought. Berkeley handyman Hal Krahn is familiar with the problems caused by the creatures."Cockatoos do create damage," Mr Krahn said."With some woods, like cedar, cockatoos particularly like the taste of it. I'm not sure what you can actually do (to deter them)." National Parks Association of NSW Illawarra branch secretary Vaughan Williamson said the cockatoos had quite a reputation."The sulphur-crested cockatoo is renowned for getting stuck into timber work. They tend to like to gnaw into the timber."Col Meharg, of Mt Kembla, said he had not noticed an increase in cockatoo activity."They seem to come and go on a rolling basis. They're here for a few days and then they go again."I think some people encourage them with seeds they leave on their verandahs."Bob Kalnin, parrot co-ordinator for NSW Wildlife Information Rescue and Education Service, said the birds were known to occasionally cause damage."The cockies are a native species and there's certainly plenty around," Mr Kalnin said."Currently there are many young cockatoos locally at a stage where they are no longer reliant on their parents to feed them."Cockatoos roost overnight in flocks and move off to feed ... not long after sunrise."They generally rest up during the day after stripping trees of leaves and bark, as well as man-made materials at times."